STRATIGRAPHY OF AL-JAZIRA AREA

N. Al-Kubaysi, Kifah; Ala,; A. Ma, Khaldoun

	STRATIGRAPHY OF AL-JAZIRA AREA
Iraqi Bulletin of Geology and Mining
Article 1, Volume 0, Issue 3, 2017, Pages 49-70
Authors
Kifah N. Al-Kubaysi; ; Khaldoun A. Ma
Abstract
The available stratigraphic data, including subsurface data, have been integrated to infer the stratigraphical evolution of the Miocene Basin in Al-Jazira Area, Northwest Iraq. The exposed rocks within the stratigraphic column are represented by four formations: Anah (Late Oligocene) Euphrates (Early Miocene), Fat'ha (Middle Miocene) and Injana (Late Mioccene). Moreover, twelve main types of Quaternary sediments are recognized. Whereas, the drilled wells in the area encountered five rock units of Miocene age (Euphrates, Dhiban, Jeribe, Fat'ha and Injana formations). The stratigraphic sequence reflects the environmental changes progressively from marine, brackish and fresh water, respectively. The Miocene Basin incorporates sediments of two successive marine sedimentary cycles (Euphrates and Fat'ha formations), each cycle starts with sea oscillation, which delineate type and distribution of the sediments. The last sea regression was commenced in the Late Miocene due to the final phase of the Tethyan Sea closure that led to deposition of Injana Formation (Late Miocene) in fluvio – lacustrine environment, contemporaneously with cycles of terrigenous – continental clastics (pre-molasse facies). The molasse facies of Pliocene (Mukdadiya Formation) is not deposited in Al-Jazira Area due to influence of initial upheaval of the Sinjar anticline in that time. The vertical tectonic movements were common in the Miocene Basin since late Early Miocene till Quaternary, as indicated by the development of Dhiban and Jeribe formations (subsurface) and the cyclicity of Fat'ha and Injana formations, as well as the presence of four levels of valley terraces.

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